*** od.c.orig	Sun Jun  2 00:20:17 1996
--- od.c	Sat Jun  1 23:38:53 1996
***************
*** 71,82 ****
--- 71,116 ----
  #define ODSETUNIT(DEV, U) \
   makedev(major(DEV), dkmakeminor((U), dkslice(DEV), dkpart(DEV)))
  
+ /* SCSI Caching page definition by Jun Obama */
+ struct scsi_caching_page_data {
+   u_char page_code;
+ #define SCSI_CACHING_PAGE_CODE	0x08
+ #define SCSI_CACHING_PAGE_PS_CURRENT	0x00
+ #define SCSI_CACHING_PAGE_PS_CHANGEABLE	0x40
+ #define SCSI_CACHING_PAGE_PS_DEFAULT	0x80
+ #define SCSI_CACHING_PAGE_PS_SAVED	0xC0
+   u_char param_len;
+   u_char flags;
+ #define SCSI_CACHING_PAGE_WCE	0x04
+ #define SCSI_CACHING_PAGE_MF	0x02
+ #define SCSI_CACHING_PAGE_RCD	0x01
+   u_char retention_priorities;
+ #define SCSI_CACHING_PAGE_DEMAND_READ_RETENTION	0xf0
+ #define SCSI_CACHING_PAGE_WRITE_RETENTION	0x0f
+   u_char disable_prefetch_transfer_len[2];
+   u_char min_prefetch[2];
+   u_char max_prefetch[2];
+   u_char max_prefetch_ceiling[2];
+ };
+ 
+ /* scsi mode sense data format copied from sd.c by Jun Obama*/
+ struct scsi_mode_sense_data {
+ 	struct scsi_mode_header header;
+ 	struct blk_desc blk_desc;
+ 	struct scsi_caching_page_data pages;
+ };
+ 
  static	errval	od_get_parms __P((int unit, int flags));
+ static	errval	od_get_mode __P((u_int32 unit, struct scsi_mode_sense_data *, u_int32 page));
+ static	errval	od_set_mode __P((u_int32 unit, struct scsi_mode_sense_data *));
+ static errval od_set_synchronize_cache_command(u_int32);
+ 
  static	void	odstrategy1 __P((struct buf *));
  
  static	int	od_sense_handler __P((struct scsi_xfer *));
  static	void    odstart __P((u_int32, u_int32));
  
+ 
  struct scsi_data {
  	u_int32 flags;
  #define	ODINIT		0x04	/* device has been init'd */
***************
*** 177,182 ****
--- 211,217 ----
  {
  	u_int32 unit;
  	struct disk_parms *dp;
+ 	struct scsi_mode_sense_data data;
  
  	struct scsi_data *od = sc_link->sd;
  
***************
*** 219,224 ****
--- 254,290 ----
  	od->flags |= ODINIT;
  	od_registerdev(unit);
  
+ 	/*
+ 	 * Write Cache Disable routine for DELTIS MOS321 1.60.
+ 	 * The bug in DELTIS MOS321 1.60 is that unable to control SCSI bus 
+ 	 * when write cache is full.
+ 	 * appended by Jun Obama 
+ 	 */
+ 	/* get changeable cache information */
+ 	od_get_mode(unit, &data, SCSI_CACHING_PAGE_CODE | SCSI_CACHING_PAGE_PS_CHANGEABLE);
+ 	{
+ 		u_char chgabl;
+ 		int chgflag = 0;
+ 		
+ 		chgabl = data.pages.flags;
+ 		/* get current cache information */
+ 		od_get_mode(unit, &data, SCSI_CACHING_PAGE_CODE);
+ 		/* if write cache is changeable to disable, change it */
+ 		if ( chgabl & SCSI_CACHING_PAGE_WCE ) {
+ 			data.pages.flags &= ~SCSI_CACHING_PAGE_WCE;
+ 			chgflag = 1;
+ 		}
+ 		/* if read cache is changeable to enable, change it */
+ 		if ( chgabl & SCSI_CACHING_PAGE_RCD ) {
+ 			data.pages.flags |= SCSI_CACHING_PAGE_RCD;
+ 			chgflag = 1;
+ 		}
+ 		/* if need, set SCSI drive to changed cache mode */
+ 		if ( chgflag ) {
+ 			od_set_mode(unit, &data);
+ 		}
+ 	}
+ 
  	return 0;
  }
  
***************
*** 485,491 ****
  	 * Check if the device has room for another command
  	 */
  	while (sc_link->opennings) {
- 
  		/*
  		 * there is excess capacity, but a special waits
  		 * It'll need the adapter as soon as we clear out of the
--- 551,556 ----
***************
*** 502,508 ****
  			return;
  		}
  		dp->b_actf = bp->b_actf;
- 
  		/*
  		 *  If the device has become invalid, abort all the
  		 * reads and writes until all files have been closed and
--- 567,572 ----
***************
*** 713,718 ****
--- 777,783 ----
  	struct scsi_link *sc_link = SCSI_LINK(&od_switch, unit);
  	struct scsi_data *od = sc_link->sd;
  	struct disk_parms *disk_parms = &od->params;
+ 	struct scsi_mode_sense scsi_cmd;
  	u_int32 sectors;
  	errval retval;
  
***************
*** 835,837 ****
--- 900,961 ----
  
  	return SCSIRET_DO_RETRY;
  }
+ /*
+  * Get the requested page into the buffer given
+  * Copied by Jun Obama from cd.c
+  */
+ static errval
+ od_get_mode(unit, data, page)
+ 	u_int32 unit;
+ 	struct scsi_mode_sense_data *data;
+ 	u_int32 page;
+ {
+ 	struct scsi_mode_sense scsi_cmd;
+ 	errval  retval;
+ 
+ 	bzero(&scsi_cmd, sizeof(scsi_cmd));
+ 	bzero(data, sizeof(*data));
+ 	scsi_cmd.op_code = MODE_SENSE;
+ 	scsi_cmd.page = page;
+ 	scsi_cmd.length = sizeof(*data) & 0xff;
+ 	retval = scsi_scsi_cmd(SCSI_LINK(&od_switch, unit),
+ 	    (struct scsi_generic *) &scsi_cmd,
+ 	    sizeof(scsi_cmd),
+ 	    (u_char *) data,
+ 	    sizeof(*data),
+ 	    OD_RETRIES,
+ 	    20000,		/* should be immed */
+ 	    NULL,
+ 	    SCSI_NOSLEEP | SCSI_NOMASK | SCSI_SILENT | SCSI_DATA_IN);
+ 	return (retval);
+ }
+ 
+ /*
+  * Set the requested page into the buffer given
+  * Copied by Jun Obama from cd.c
+  */
+ errval
+ od_set_mode(unit, data)
+ 	u_int32 unit;
+ 	struct scsi_mode_sense_data *data;
+ {
+ 	struct scsi_mode_select scsi_cmd;
+ 
+ 	bzero(&scsi_cmd, sizeof(scsi_cmd));
+ 	scsi_cmd.op_code = MODE_SELECT;
+ 	/* scsi_cmd.byte2 |= (SMS_PF | SMS_SP); */
+ 	scsi_cmd.byte2 |= SMS_PF;
+ 	scsi_cmd.length = sizeof(*data) & 0xff;
+ 	data->header.data_length = 0;
+ 	return (scsi_scsi_cmd(SCSI_LINK(&od_switch, unit),
+ 		(struct scsi_generic *) &scsi_cmd,
+ 		sizeof(scsi_cmd),
+ 		(u_char *) data,
+ 		sizeof(*data),
+ 		OD_RETRIES,
+ 		20000,		/* should be immed */
+ 		NULL,
+ 		SCSI_NOSLEEP | SCSI_NOMASK | SCSI_SILENT | SCSI_DATA_OUT));
+ }
+ 
+